Sort not working

 1 // compute mean and median temperature
  2 #include <iostream>
  3 #include <string>
  4 #include <vector>
  5 #include <algorithm>
  6
  7 using std::cout;
  8 using std::cin;
  9 using std::string;
 10 using std::vector;
 11
 12 int main()
 13 {
 14     vector<double> temps;
 15     for (double temp; cin>>temp; )
 16         temps.push_back(temp);
 17
 18     // compute mean temperature
 19     double sum = 0;
 20     for (int x : temps) sum += x;
 21     cout << "Average temperature: "  << sum/temps.size() << '\n';
 22
 23     // compute median temperature
 24     sort(temps);
 25     cout << "Median temperature: " << temps[temps.size()/2] << '\n';
 26
 27     return 0;
 28 }